Ubuntu 配置NTP Server

Ubuntu安装NTP Server很简单，分位3步走：

第一步：安装NTP

root@cephadmin:~/ceph-cluster# apt-get install ntp
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
  libopts25
Suggested packages:
  ntp-doc
The following NEW packages will be installed:
  libopts25 ntp
 upgraded,  newly installed,  to remove and  not upgraded.
Need to get  kB of archives.
After this operation, , kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get: http://cn.archive.ubuntu.com/ubuntu/ trusty/main libopts25 amd64 1:5.18-2ubuntu2 [55.3 kB]
Get: http://cn.archive.ubuntu.com/ubuntu/ trusty-updates/main ntp amd64 1:4.2.6.p5+dfsg-3ubuntu2.14.04.10 [421 kB]
Fetched  kB in 0s ( kB/s)
Selecting previously unselected package libopts25:amd64.
(Reading database ...  files and directories currently installed.)
Preparing to unpack .../libopts25_1%3a5.-2ubuntu2_amd64.deb ...
Unpacking libopts25:amd64 (:5.18-2ubuntu2) ...
Selecting previously unselected package ntp.
Preparing to unpack .../ntp_1%3a4.2.6.p5+dfsg-3ubuntu2.14.04.10_amd64.deb ...
Unpacking ntp (:4.2..p5+dfsg-3ubuntu2.14.04.) ...
Processing triggers for ureadahead (0.100.-) ...
ureadahead will be reprofiled on next reboot
Processing triggers for man-db (2.6.7.1-) ...
Setting up libopts25:amd64 (:5.18-2ubuntu2) ...
Setting up ntp (:4.2..p5+dfsg-3ubuntu2.14.04.) ...
 * Starting NTP server ntpd                                                                                                                                                 [ OK ]
Processing triggers for libc-bin (2.19-0ubuntu6) ...
Processing triggers for ureadahead (0.100.-) ...

root@cephadmin:~/ceph-cluster# service ntp status
 * NTP server is running

第二步：修改ntp.conf配置文件

1) 添加公网NTP Server

　server 120.24.166.46   (阿里云NTP Server)

2) 允许的NTP Client网段

restrict 10.138.0.0 mask 255.255.0.0 nomodify

# Enable this if you want statistics to be logged.
#statsdir /var/log/ntpstats/    #也可以开启NTP log

statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable

# Specify one or more NTP servers.

# Use servers from the NTP Pool Project. Approved by Ubuntu Technical Board
# on -- (LP: #). See http://www.pool.ntp.org/join.html for
# more information.
server 120.24.166.46   # 阿里云NTP Server
server 127.127.1.0     # 如果公网NTP不可用时，将使用Local时间作为NTP服务提供给NTP Client。

# Use Ubuntu's ntp server as a fallback.
server ntp.ubuntu.com

# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for
# details.  The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a configuration
# that might be intended to block requests from certain clients could also end
# up blocking replies from your own upstream servers.

# By default, exchange time with everybody, but don't allow configuration.
restrict - default kod notrap nomodify nopeer noquery
restrict - default kod notrap nomodify nopeer noquery
restrict 192.168.20.0 mask 255.255.255.0 nomodify   # 允许的NTP Client网段
# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::

第三步：重启NTP服务，并在客户端验证

root@ntpserver:~/ceph-cluster# service ntp restart
 * Stopping NTP server ntpd                                           [ OK ]
 * Starting NTP server ntpd                                           [ OK ] 

root@ntpclient:/etc/ceph# ntpdate ntpserver
 Jan :: ntpdate[]: adjust time server 192.168.20.177 offset 0.209691 sec
root@ntpclient:/etc/ceph# 

未完待续......